Portable radio receiving set



May 11 1926. 1,584,220

H. FARKOUH PORTABLE RADIO RECEIVING SET Filed May 21, 1923 5 Sheets-Sheet 1 Y May 11 192 1,584,220

H. FARKO'UH I PORTABLE RADIO RECEIVING SET Filed May 21 1923 3 sheets-Sheet 2 r? 1 H5 x1 May 11 1926.

H. FARKOUH PORTAB-LE RADIO RECEIVING SET Filed May 21, 1925 3 SheetEs-Sheet s this latter side of th Patented May 11, 19 26.

HENRY FAfRKOUH, OF BROOKLYN, NEW YORK.

PORTABLE RADIO REOEIVIN G SET.

Application filed May 21,

This invention relates apparatus havin more particular reference to a portablera io receivin set for rece ving broadcasted speech an music, the n- 5 vention having for an object the provision .of a compact, self contained portable radio set in which the antenna takes the form of an enclosed special loop, the whole apparatus being contained in a single case; A 10 further object of the invention is to provide ,a portable radio set characterized generally to radio tion of static and 'toprovide a" set which is very sensitive and will pick radio signals at 1 any. elevation, regardless where it is operated. A A

For further comprehension of the invention, and of the objects and advantages thereof, reference will be .had to the follow- 3 ing description and accom ayning drawings,

. and to theappended claims in which the various novel features of the invention are 'more particularly set fort Fig. 1 of the drawingsis a perspect ve 25 view showing my improved radio set with the case closed.

Fig. 2 is a similar view but showing the cover thrown open and the set ready for use.

- 30 Fig. 3 is atop edge: view with parts in horizontal section. Fig. 4 is a rear view of the panel board. Fig. 5 is a. transverse vertical sectional view'taken on the line 5-5 of Fig. 4. ig. 6 is a diagram of the wiring circuit. I Fig. 7 is an end view indicating the means for supporting position. I v Fig. 8 is a detail rear elevation showing the said supporting means. v Fig. 9 is a horizontal sectional View taken on the line 9-9 of Fig. 8. shown in the drawings I have embqdidmy invention in a-readily portable un it" Whose enclosing casing comprises the body 10 and cover 11. These parts areof general construction such as is used in suit cases, and they may be made by fibre suitably reinforced at the corners and'edges as shown. A handle 12 for carrying purposes is. provided o'n-that side'of the case to which the coveris hinged, anordina'ry lock 13 and h -f hasps 14 being provided for the cover. On

berlmobs or feet 1? are provided to preby sharp-' ness of tuning and selection and the el1m1naset here shown is of its free end which the set in proper receiving speaker is so placed on e case a number of rub-.

1923. Serial K0,, 640,385.

vent jarringof the set when the case is set down.

The antenna for the set of the loop 'type is carried by the cover and consists of a Wire 18 of suitable length and spacing arrange: ment looped around pins 19 carried by flat strips 20 secured to the *inner face of the cover andextending diagonally from the corners thereof. The ends of this antenna connect to the loose wires which lead to theusual devices.

Hinged at one end to the end Wall of the case 10 as at is a panel board 26 which extends across the front of the case and carries the various elements of the'set. The

the type comprising a detector and t-hree stages of radio frequency and 3 stages "of audio frequency amplification, and to supportthe various tubes and transformers a shelf 27 is fixed to the back of the panel by the brackets 28. The panel 26 .and shelf 27 are preferably of hardrubber composition having a mahogany finish. The panel 26 also supports the loud speaker, comprising the horn '29 andthe phone element 30, the mouth of the horn extending through the panel. The usual free cord 32 leads from the phone and has the lug '33 on engages 'wit suitable jacks mounted on the-panel board.

An objectionable factor common to most portable radio -receiving sets appears to be the howling of the electron tubes, due to the mechanical vibrations of the loud speaker being transmitted to the grid elements of the tubes. Portable radio receiving sets usually have loopantennae, which, of course have connections to the grid of the tubes, and if v the vibrations of the loud speaker are permitted to reach the-loop antenna,- howling I will result in the tubes. Also, ifthe lou the set so as' to allow the mechanical vibrations to reach the tubes, howling will result. I have discovered that if the-loud speaker is mounted in the plane of the front anel, as above described, and if a shelf, suc i as 27, is mounted r at right angles to the plane ofthe panel, the mechanical vibrations in the panel .set up by the loud speaker, are not very readily communicated to the shelf, and thereforethe owling of tubes due to greatly reduced when mounted on said shelf. Furthermore with the loud speaker mounted in the panel, and the loop antenna mounted such vibrationsare within the box,

7 spectively transformer,

. Vernier condenser To stabilize-the loop the vibrations seem to be quite capable of reaching it, because of its great sensitivity to. such vibrations. But with the loop mounted on the cover, and the loud speaker on the panel, the vibrations affect the loop to a very much lesser degree.

The tubes which I prefer to employ are those known in the trade as model UV 199 and these are arranged in a row along theshelf 27 with the detector tube. indicated at 35, in the centre, and the audio and radio frequency amplification tubes indicated reat 36 and 37 arranged on opposite sides of the detector tube. These tubes all include the usual plate, grid and filament.

Upon the shelf 27, just to the rear of the tubes, are mounted the transformers which comprise three radio frequency transformers38 and three audio frequency trans formers 39. The radio transformers are preferably. the Rasla Radio Service Laboratories RTS transformers, while the audio transformers are preferably two WD 12 Amplex Laboratories, to 1 ratio transformers and for the third audio stage. The second stage audiotransformers are placed at 90 degrees to the 1st and 3rd stage transformers.- The set also includes three jacks which are mounted on the panel 26 under the shelf 27 and which are connected to the detector and the different stages of audio amplification.

The loop 18 is .tuned by a variable condenser 41 of the Varioden type, and a small 42 of the Chelton type.

ometer 43 is placed across the leads from the A battery. The filament circuit 45 to the en'- tire series of tubes is controlled by a 6 ohm rheostat inserted therein in the negative side, while like rheostats 46 in the positive side and 47 in the negative side respectively control the individual circuits to the sets of radio amplification and audio amplification tubes. A 30 ohm rheostat 48 in the positive side controls the filament circuit of'the detector tube.

Of the jacks abovereferredto one double circuit jack 50' is arranged in the detector tube to cut ip plate circuit of the detector on the 3rd R. F. and detector tubes.

, second double circuit jack 51 is arranged in the 3rd R. F. and

two A. F. Asmgle circuit jack 52 is arranged in the plate circuit of the 3rd A. F. stage to get the out-.

ut of the whole seven tubes. The usual A and B batteries, indicated respectively at 53 and 54 are placed freely in the case 10 under the shelf 27.

In the use of the set the case is opened and the cover swun up to vertical position, while the body of the case is preferably ar-' rangpd at a slight angle to thehorizontal ass through to form a has mounted one Thordarson, 6 to 1 ratio,

a 200 ohm potent1-' speaker will produce a own, the parts being arranged to have the loop 18 at right angle to the path of the waves. The apparatus is then tuned up in the manner common with the loop, radio audio amplification sets.

To support the case 10 and cover 11 at the proper angles I provide a simple device which is in the form of a fiat bar which is slidably held when the set is not inuse by a pair of cleats 61 and 62 fixed to the cover 1.1 and which then engage opposite ends of this bar. to the lower edge of the case body and is adapted to have the bar 60 projected theresupport or strut which holds the said body tilted. The bar 60 has a number of suitably spaced apertures 64* each of the cleats62 and 63.

therein, while thereon a pin 65.carr1ed on the end of a fiat spring 66 fixed at its other end to the cleat, this pin being adapted to take into selected ones of the said apertures to hold the parts in proper position. Each of these pins is formed with a knob or head 67 whereby they may be grasped when they are to be withdrawn from engagement with the bar. When the device is not in use the bar extends across the cover 11 and is held against sliding movement by engagement of the pin on the cleat 62 with the lower opening 64 in the bar. In use the bar 60 assumes the position shown in Fig. 7', with the pins on the cleats 62 and 63 respectively engaged in suitable apertures in the bar.

I have found by experiment, and by actual reduction to practice, that a set of a high degree of efficiency, and capable of clearly receivin broadcasted speech and music up to a ra ius of approximately one hundred miles, covering a range of 200 to 6QO meters wave length, depending on atmospheric conditions, can be contained ina case having dimensions of 20 long, 10" wide, and 6" deep, and with a weight not to exceed 20 lbs. The set is thus readily portable. The best unit quantities for the various instruments I have also found by actual test to be those indicated in Fig. 6. The loud volume of sound capable of filling a room seating 500 people. It can be readily transported on automobiles, launches, and the like and will operate during travel. It constitutes briefly, a set characterized by neatness, compactness, efficiency and ease of setting up and general manipulation.

While I have described myportable radio receiving set Another cleat 63 is fixed tubes mounted on said shelf, the er mounted on said panel board of said shelf, With its mouth 1 panel board, and th a loop carried by loud speakat one side ying in said with a front the grids of said electron. tubes.

able case,

cover, whereby the mechanical vibrations of the 0nd speaker are damped'froln reaching 3. In a radio receiving apparatus, able case, a cover hinged thereto, and normally carried by said to support the case tilted, and the cover vertical.

a portapparatus, ab e case, a coyer hinged thereto, and

ti-cal, and gaging said strut.

5. n a radio receiving apparatus, a porta cover hinged thereto, and a strut normally carried by said cover and adapted to support the case tilted, and the cover vertical, and cleats on said case and cover engaging said strut, and by said projecting cleats into saidtstrut.

In testimony whereof I have aflixed myapertures in signature.

HENRY FARKOUH.

3o a strut cover and adapted pins carried 

